Method and system for transferring wireless transmit/receive unit-specific information

ABSTRACT

The present invention is related to a method and system for transferring wireless transmit/receive unit (WTRU)-specific information to support enhanced uplink (EU) operation in a wireless communication system. A radio network controller (RNC) obtains WTRU-specific information, and transfers the WTRU-specific information to the Node-Bs. Each Node-B is configured to schedule uplink transmissions from a WTRU and utilizes the WTRU-specific information in operation of EU transmissions.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/980,723, filed Nov. 3, 2004, which claims the benefit of U.S.Provisional Application No. 60/519,436 filed Nov. 12, 2003, which isincorporated by reference as if fully set forth.

FIELD OF INVENTION

The present invention is related to a wireless communication system.More particularly, the present invention is a method and system fortransferring wireless transmit/receive unit (WTRU)-specific information.

BACKGROUND

In wireless communication systems implementing the Third GenerationPartnership Project (3GPP) standards, the Radio Network Controller (RNC)maintains overall control of transmissions to WTRUs and knows thecapabilities of each WTRU. However, the current scheme often incursproblems with throughput and transmission latency. In order to improveupon the current scheme, the Node-Bs may be relied upon to schedule andassign uplink (UL) radio resources to WTRUs. Node-Bs can make moreefficient decisions and manage UL radio resources on a short-term basisbetter than an RNC, even if the RNC retains overall control overNode-Bs.

In order for a Node-B to assign UL radio resources to WTRUs in enhanceduplink (EU) operation, the Node-B must know several WTRU-specificparameters. Under the current 3GPP standard, only the RNC knows theWTRU-specific parameters. The RNC obtains this information via radioresource control (RRC) messages conveying WTRU-specific information.Therefore, it is necessary to forward the information to the Node-B forproper scheduling of radio resources in EU transmissions.

SUMMARY

The present invention is a method and system for transferringWTRU-specific information to the Node-Bs to support EU operation in awireless communication system. An RNC obtains WTRU-specific informationand transfers the WTRU-specific information to the Node-Bs. Each Node-Bis configured to schedule UL transmissions from a WTRU and utilizes theWTRU-specific information in operation of EU transmissions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a wireless communication system.

FIG. 2 is a block diagram for transferring WTRU-specific informationamong network entities in accordance with the present invention.

FIG. 3 is a flow diagram of a process for transferring WTRU-specificinformation in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described with reference to the drawingfigures wherein like numerals represent like elements throughout.

Hereafter, the terminology “WTRU” includes but is not limited to a userequipment, a mobile station, a fixed or mobile subscriber unit, a pager,or any other type of device capable of operating in a wirelessenvironment. When referred to hereafter, the terminology “Node-B”includes but is not limited to a base station, a site controller, anaccess point or any other type of interfacing device in a wirelessenvironment.

FIG. 1 is a block diagram of a wireless communication system 100 inwhich an RNC 106 controls a plurality of Node-Bs 104, (only one beingshown), and each Node-B 104 covers one or more cells 108 a, 108 b, 108c. There is typically one “serving cell” that serves the WTRU 102, butthe WTRU 102 may be in soft handover with several cells at one time. Forexample, in EU operation, UL transmissions are scheduled and radioresources are assigned by the Node-B 104 to the WTRU 102 through a“serving” cell, for example cell 108 c, to which the WTRU 102 hasestablished a connection. The WTRU 102 may also be connected to othercells in support of soft handover.

FIG. 2 is a block diagram of a system 200 for transferring WTRU-specificinformation to support EU operation in accordance with the presentinvention. The system 200 includes at least one WTRU 202, at least oneNode-B 204, and at least one RNC 206. Communication links supportsignaling 208, 210, 212 between the WTRU 202, the Node-B 204 and the RNC206. Initially, an RNC 206 obtains WTRU-specific information from a WTRU202 using RRC messaging 208 during the initial connection. Theinformation transferred from the WTRU 202 that is needed by the Node-B204 is primarily physical transmission and reception capabilityinformation. The WTRU-specific information is then forwarded from theRNC 206 to a Node-B 204 to be used in scheduling UL transmissions forthe WTRU 202.

A new signaling procedure may be utilized to transfer the informationfrom the RNC 206 to the Node-B 204. Alternatively, the existingmechanisms, (for example the Radio Link Setup procedure over Iur and Iubinterfaces), may be modified in order for the RNC 206 to forwardrelevant WTRU-specific information to the Node-B 204. Although thespecific protocol or format used to transmit the information is notcritical to the present invention, by way of the present example, thetransfer of the information from the RNC 206 to the Node-B 204 is viaIub interface 210 and Iur interface. The RNC 206 transfers theWTRU-specific information to the Node-B 204 via the Radio NetworkSubsystem Application Protocol (RNSAP) control procedure (over the Iurinterface) and the Node B Application Part (NBAP) control protocol (overthe Iur interface). This information may be signaled along with theRadio Link Setup procedure in the UTRAN.

The forwarding of the WTRU-specific information may occur in response toa discrete event, such as when the WTRU 202 enters or establishesservice in the service area covered by the RNC 206, or when the WTRU 202leaves the service area. Alternatively, the forwarding of the WTRUspecific information may occur periodically during the lifetime of aradio link whereby the WTRU 202 updates the WTRU-specific information.

The transfer of the WTRU-specific information may be initiated by eitherthe RNC 206 or the Node-B 204. If it is initiated by the RNC 206, theWTRU-specific information is transferred at the initiation of theservice or at the detection of change of WTRU-specific information fromthe RNC 206 to the Node-Bs 204. Alternatively, a Node-B 204 may requestthe information to be forwarded from the RNC 206 to the Node-B 204, andthe RNC 206 subsequently transfers the information upon receipt of therequest from the Node-B 204.

WTRU-specific information includes, but is not limited to: WTRUcapabilities with respect to EU; information affecting data rates andthroughput; and information regarding physical and transport channelcharacteristics allocated to a WTRU and relevant to a Node-B.

Information affecting data rates and throughput includes, but is notlimited to: the number of multi-codes supported for UL physicalchannels; modulation schemes and coding rates supported for UL physicalchannels; automatic repeat request (ARQ) buffer or memory sizes in theWTRU; WTRU power class; number of hybrid ARQ (H-ARQ) processes supportedin the WTRU; the form of available WTRU memory for EU; supported bitrates and bits receivable per transmit time interval (TTI) at layer 1(L1) or layer 2 (L2) level; and capability for simultaneous reception ofother than EU-specific channels by the WTRU.

Information on physical and transport channel characteristics includes,but is not limited to: maximum or minimum power settings of UL or DLphysical channels; shared or dedicated physical channels allocated bythat WTRU (spreading and scrambling codes, periodicity or enumerationsof time intervals when the WTRU can be allocated shared channel usage);and information on HSDPA WTRU capability class for DL services.

The present invention is applicable to both frequency division duplex(FDD) and time division duplex (TDD) modes. Because of the commonalityof higher layer (RRC or via Iur/Iub) signaling for FDD and TDD modes,all parameters listed above also apply to a TDD mode. For a TDDapplication, some TDD-only parameters should also be included, such asnumber of EU TDD service timeslots per WTRU, number of EU TDD spreadingcodes per WTRU and per time slot, and allowable and configurable powersettings of physical channels of EU TDD WTRU per timeslot and per WTRU.

High Speed Data Packet Architecture (HSDPA) WTRU capabilities for DLdata transmissions have several common attributes to EU WTRUcapabilities for UL data transmissions. Since a Node-B providesscheduling of both DL HSDPA and UL EU services, the Node-B has theability to dynamically distribute capabilities between UL and DLservices, potentially on a TTI basis, and to better determine UL and DLtransmissions for improved quality of service (QoS) and more efficientuse of radio resources.

FIG. 3 is a flow diagram of a process 300 for transferring WTRU-specificinformation in accordance with the present invention. A WTRU 202establishes a connection 212 to a Node-B 204 in a region covered by anRNC 206 (step 202). The RNC 206 obtains WTRU-specific information fromthe WTRU 202 using RRC messaging (step 204). The RNC 206 transfers theWTRU-specific information to the Node-B 204 (step 206). The transfer ofWTRU-specific information may be initiated by the Node-B 204. The Node-B204 is configured to schedule UL transmissions from the WTRU 202, andutilize the WTRU-specific information in operation of EU transmission.

Although the features and elements of the present invention aredescribed in the preferred embodiments in particular combinations, eachfeature or element can be used alone (without the other features andelements of the preferred embodiments) or in various combinations withor without other features and elements of the present invention.

1. A method for efficient scheduling of enhanced uplink (EU)transmissions, the method comprising: a Node-B receiving wirelesstransmit/receive unit (WTRU)-specific information from a radio networkcontroller (RNC), the WTRU-specific information being used forscheduling EU transmissions from a WTRU; and the Node-B scheduling EUtransmissions from the WTRU to the Node-B utilizing the WTRU-specificinformation.
 2. The method of claim 1 wherein the WTRU-specificinformation includes WTRU capability information with respect to EU andhigh speed downlink packet access (HSDPA).
 3. The method of claim 1wherein the WTRU-specific information includes information affectingdata rates and throughput.
 4. The method of claim 1 wherein theWTRU-specific information includes information on physical and transportchannel characteristics.
 5. The method of claim 1 wherein theWTRU-specific information includes time division duplex (TDD)-specificparameters.
 6. The method of claim 1 wherein the WTRU-specificinformation is received upon establishment of a service and upon anychange of the WTRU-specific information.
 7. The method of claim 1wherein the WTRU-specific information is received periodically.
 8. ANode-B for efficient scheduling of enhanced uplink (EU) transmissions,the Node-B comprising: a receiver for receiving wirelesstransmit/receive unit (WTRU)-specific information from a radio networkcontroller (RNC), the WTRU-specific information being used forscheduling EU transmissions from a WTRU; and a scheduler configured toschedule EU transmissions from the WTRU to the Node-B utilizing theWTRU-specific information.
 9. The Node-B of claim 8 wherein theWTRU-specific information includes WTRU capability information withrespect to enhanced uplink (EU) and high speed downlink packet access(HSDPA).
 10. The Node-B of claim 8 wherein the WTRU-specific informationincludes information affecting data rates and throughput.
 11. The Node-Bof claim 8 wherein the WTRU-specific information includes information onphysical and transport channel characteristics.
 12. The Node-B of claim8 wherein the WTRU-specific information includes time division duplex(TDD)-specific parameters.
 13. The Node-B of claim 8 wherein theWTRU-specific information is received upon establishment of a serviceand upon any change of the WTRU-specific information.
 14. The Node-B ofclaim 8 wherein the WTRU-specific information is received periodically.